Structural modulation of casein peptide-hydroxytyrosol self-assembled nanocomplexes: Enhanced gastrointestinal...

Food-derived bioactive peptides frequently face gastrointestinal instability, limiting their functional applications. This study investigated the assembly mechanisms, stability, and digestive characteristics of casein hydrolysate-hydroxytyrosol (CH-HT) complexes formed via self-assembly. Multispectral and thermodynamic analysis revealed CH and HT bind spontaneously mainly through hydrophobic interactions, which induced a disordered conformation in CH. These structural changes were further confirmed by molecular docking and molecular dynamics simulations. In vitro digestion indicated HT effectively prevented CH aggregation during gastric digestion while enhancing its intestinal liberation, ultimately increasing DPPH (28.04 %) and ABTS (49.91 %) radical scavenging capacity at the end of intestinal digestion. Cellular viability assays indicated that the complexes have excellent biosafety profiles on RAW264.7 cells and significantly reduced the ROS level in oxidative damage, showing the potential to enhance the transport of antioxidants to the intestine. These results provide a strategy for the peptide-polyphenol self-assembly to improve the stability of bioactive peptides in functional foods.